Enhanced production of interleukin 1 and tumor necrosis factor by peripheral monocytes after lentinan administration in patients with gastric carcinoma

Lentinan ameliorates burn sepsis by attenuating CD4+ CD25+ Tregs

AIM

The aim of our study was to investigate the effect of lentinan on regulatory T cells (Tregs) in sepsis, especially on the generation of interleukin (IL)-10 via regulation of Erk-FoxO1 signaling.

METHODS

BalB/c mice were randomized into five groups: sham group, the group with burns plus Pseudomonas aeruginosa infection, and the groups with burns plus P. aeruginosa infection administered 40, 100, and 250mg/kg of lentinan. The mice were sacrificed on postburn days 0, 1, 2, 3, and 4, respectively, with eight animals per group at each time point. The peripheral blood CD4⁺ CD25⁺ Tregs and CD4⁺ T cells were isolated using magnetic microbeads. The phenotypes were analyzed by flow cytometry. The cytokine levels were determined with enzyme-linked immunosorbent assay (ELISA). Signal transduction was studied by Western blot, quantitative polymerase chain reaction (qPCR), and luciferase assay.

RESULTS

The IL-10-producing capacity of CD4⁺ CD25⁺ Tregs was significantly enhanced in the group with burns plus P. aeruginosa infection, compared with the sham group. Administration of lentinan significantly decreased IL-10 production and FoxP3 expression of CD4⁺ CD25⁺ Tregs. The proliferative activities of CD4⁺ T cells, however, were restored. Lentinan decreased lipopolysaccharide (LPS)-induced IL-10 production in the Tregs isolated from burned mice. In addition, lentinan attenuated LPS-stimulated Erk-FoxO1 activation.

CONCLUSIONS

Lentinan may improve the outcome of postburn sepsis by suppressing LPS-triggered Erk-FoxO1 activation. Consequently, the hyperfunction of CD4⁺ CD25⁺ Tregs is inhibited, leading to a shift in the inflammatory status from Th2 to Th1 in postburn sepsis.

Immunomodulatory activity of a novel, synthetic beta-glucan (β-glu6) in murine macrophages and human peripheral blood mononuclear cells

Natural β-glucans extracted from plants and fungi have been used in clinical therapies since the late 20th century. However, the heterogeneity of natural β-glucans limits their clinical applicability. We have synthesized β-glu6, which is an analog of the lentinan basic unit, β-(1→6)-branched β-(1→3) glucohexaose, that contains an α-(1→3)-linked bond. We have demonstrated the stimulatory effect of this molecule on the immune response, but the mechanisms by which β-glu6 activates innate immunity have not been elucidated. In this study, murine macrophages and human PBMCs were used to evaluate the immunomodulatory effects of β-glu6. We showed that β-glu6 activated ERK and c-Raf phosphorylation but suppressed the AKT signaling pathway in murine macrophages. Additionally, β-glu6 enhanced the secretion of large levels of cytokines and chemokines, including CD54, IL-1α, IL-1β, IL-16, IL-17, IL-23, IFN-γ, CCL1, CCL3, CCL4, CCL12, CXCL10, tissue inhibitor of metalloproteinase-1 (TIMP-1) and G-CSF in murine macrophages as well as IL-6, CCL2, CCL3, CCL5, CXCL1 and macrophage migration inhibitory factor (MIF) in human PBMCs. In summary, it demonstrates the immunomodulatory activity of β-glu6 in innate immunity.

Enhancing effects of new biological response modifier beta-1,3 glucan sulfate PS3 on immune reactions

Glucans have a long history as non-specific biological modulators; however, but the search for optimal chemical configuration is still on. The objective of this study was to evaluate intraperitoneal application of PS3, a sulfated derivative of a (1-->3)-beta-D-glucan isolated from sporophytes of Laminaria digitata. PS3 showed significant stimulation of phagocytic activity as well as potentiation of synthesis and release of IL-2 by splenocytes. In addition, PS3 increased NK cell-mediated killing of tumor cells both in vitro and in vivo. When combined, our observations suggest that PS3 is similarly effective as native non-sulfated (1-->3)-beta-D-glucan and is generally more active than lentinan.

Glucan and resveratrol complex - possible synergistic effects on immune system

BACKGROUND

Recent data showing that glucan elicited defense responses in grapevine and induced protection via induction of resveratrol production led us to evaluate the possible synergetic effects of glucan and resveratrol complex on immune reactions.

METHODS

We measured phagocytosis using HEMA particles, expression of cell surface markers via fl ow cytometry, expression of cytokines using ELISA, recovery after fluorouracil-induced leucopenia and effects on gene expression via RT-PCR.

RESULTS

Our results showed that both glucan and resveratrol complex stimulated phagocytosis of blood leukocytes, caused increase in surface expression of CD(+) splenocytes and showed higher restoration of spleen recovery after experimentally induced leucopenia. In all these cases, strong synergetic effects were observed. When we measured the effects of these substances on expression level of NF-kappaB2, Cdc42 and Bcl-2 in breast cancer cells, upregulation of Cdc42 expression was evident only using both immunomodulators in combination.

CONCLUSIONS

In conclusion, our data suggest significant synergy in stimulation of immune reactions and support further studies of these natural immunomodulators.

Correlation of structure to antitumor activities of five derivatives of a beta-glucan from Poria cocos sclerotium

A water-insoluble (1-->3)-beta-D-glucan isolated from fresh sclerotium of Poria cocos was, respectively, sulfated, carboxymethylated, methylated, hydroxyethylated, and hydroxypropylated, to afford five water-soluble derivatives. Their weight-average molecular masses (Mw) and intrinsic viscosities ([eta]) were determined by size-exclusion chromatography combined with laser light scattering (SEC-LLS), LLS, and viscometry in phosphate buffer solution (PBS) at 37 degrees C. The antitumor activities, against Sarcoma 180 tumor cell (S-180) and gastric carcinoma cell strain (MKN-45 and SGC-7901) of the native beta-glucan and the five derivatives, were tested in vitro and in vivo. The Mw values of the five derivatives in PBS were determined to be 3.8 x 10(4), 18.9 x 10(4), 16.0 x 10(4), 76.8 x 10(4), and 224.3 x 10(4), respectively. The high Mw values of the hydroxyethylated and hydroxypropylated derivatives in aqueous solution resulted from aggregation, and their true Mw values obtained in dimethyl sulfoxide were 20.1 x 10(4) and 19.1 x 10(4). The sulfated and carboxymethylated derivatives having DS of 1.0-1.3 show good water solubility, and exist as relatively expanded chains in aqueous solution. Interestingly, the native beta-glucan did not show antitumor activity, whereas the sulfated and carboxymethylated derivatives exhibit significant antitumor activities against S-180 and gastric carcinoma tumor cells. This work showed that good water solubility, relatively high chain stiffness, and moderate molecular mass of the derivatives in aqueous solution contribute beneficial to enhancement of antitumor activity.

Effects of marine beta-1,3 glucan on immune reactions

Glucans have a long history as nonspecific biological modulators. A novel glucan-Phycarine-was isolated from sporophytes of Laminaria digitata. Phycarine showed significant stimulation of phagocytic activity as well as potentiation of synthesis and release of IL-1, IL-6 and TNF-alpha. In addition, Phycarine increased NK cell-mediated killing of tumor cells both in vitro and in vivo while acting via complement receptor type 3 (CR3) receptors.

Induction of secretory and tumoricidal activities in peritoneal macrophages activated by an acidic heteropolysaccharide (ARAGAL) from the gum of Anadenanthera colubrina (Angico branco)

The immunomodulatory and anti-tumoral effects of an acidic heteropolysaccharide containing mainly galactose and arabinose (ARAGAL), isolated from the gum of the leguminous tree Anadenanthera colubrina (Angico branco) native to Brazil, were studied. It has been demonstrated that activation of mice peritoneal macrophages both in vivo and in vitro, increases phagocytic ability and anion superoxide production. In order to obtain further insights on the biological effects of ARAGAL, the capacity of eliciting peritoneal macrophages and tumor necrosis factor-alpha (TNF-alpha) production, and anti-tumoral effect against Sarcoma 180 (S-180), are now evaluated. Cell eliciting activity was observed in ARAGAL-treated animals in a dose dependent manner. Treatment of animals with 50, 100 or 200 mg/kg of ARAGAL increased peritoneal exudate cell (PEC) numbers by approximately 18, approximately 44 and approximately 88%, respectively. ARAGAL also increased 26-fold TNF-alpha production by peritoneal macrophages. Macrophages, treated in vitro for 18 h with ARAGAL, were able to kill Sarcoma 180 cells, as observed by their structures inside the macrophage cytoplasm. ARAGAL (100 mg/kg) showed anti-tumoral activity against S-180 in ascites or solid tumors, the tumoral inhibition being 63 and 38%, respectively. The results suggest a possible role as a BRM for ARAGAL.

Effects of lentinan on broiler splenocyte proliferation, interleukin-2 production, and signal transduction

Lentinan (LEN) is an intensively studied beta-glucan that has been shown to have immunostimulating and antitumor functions. However, it currently is not used in veterinary practice and animal production. This study was conducted to investigate the impacts of LEN on broiler splenocyte proliferation, interleukin-2 (IL-2) production, and to explore its effects on receptor signal transduction by determining signaling molecules, including nitric oxide (NO), cytosolic-free Ca2+, cytosolic cyclic adenosine monophosphate (cAMP), and cyclic guanosine monophosphate (cGMP). The results showed that compared to the control all three measured doses, including 40, 80, and 160 microg/mL LEN, increased splenocyte proliferation and IL-2 production (P < 0.05). Lentinan increased splenocyte NO production and cytosolic-free calcium concentration in a dose-dependent manner (P < 0.001). After incubating splenocytes for 20 min, LEN increased intracellular cAMP and cGMP concentrations at a dose of 80 and 160 microg/mL, respectively. However, after incubating the splenocytes for 60 min, LEN had no effect on cytosolic cAMP and cGMP concentration irrespective of the LEN dosage. Those results indicated that LEN had immunostimulatory effects on splenocytes by increasing splenocyte proliferation and IL-2 production and by activating splenocyte receptor signal transduction.

Pilot study of a specific dietary supplement in tumor-bearing mice and in stage IIIB and IV non-small cell lung cancer patients

Previously, a specific dietary supplement, selected vegetables (SV), was found to be associated with prolonged survival of stage III and IV non-small cell lung cancer (NSCLC) patients. In this study, several anticancer components in SV were measured; the anticancer activity of SV was assessed using a lung tumor model, line 1 in BALB/c mice. SV was also used in conjunction with conventional therapies by stage IIIB and IV NSCLC patients whose survival and clinical responses were evaluated. A daily portion (283 g) of SV was found to contain 63 mg of inositol hexaphosphate, 4.4 mg of daidzein, 2.6 mg of genistein, and 16 mg of coumestrol. Mouse food containing 5% SV (wt/wt) was associated with a 53-74% inhibition of tumor growth rate. Fourteen of the 18 patients who ingested SV daily for 2-46 months were included in the analyses; none showed evidence of toxicity. The first lead case remained tumor free for > 133 months; the second case showed complete regression of multiple brain lesions after using SV and radiotherapy. The median survival time of the remaining 12 patients was 33.5 months, and one-year survival was > 70%. The median survival time of the 16 "intent-to-treat" patients (including ineligible patients) was 20 months, and one-year survival was 55%. The Karnofsky performance status of eligible patients was 55 +/- 13 at entry but improved to 92 +/- 9 after use of SV for five months or longer (p < 0.01). Five patients had stable lesions for 30, 30, 20, 12, and 2 months; two of them, whose primary tumor was resected, used SV alone and demonstrated an objective response of their metastatic tumors. In addition to the two lead cases, eight patients had no new metastases after using SV. Three patients had complete regression of brain metastases after using radiotherapy and SV. In this study, daily ingestion of SV was associated with objective responses, prolonged survival, and attenuation of the normal pattern of progression of stage IIIB and IV NSCLC. A large randomized phase III clinical trial is needed to confirm the results observed in this pilot study.

Molecular cloning and expression analysis of carp (Cyprinus carpio) interleukin-1 beta, high affinity immunoglobulin E Fc receptor gamma subunit and serum amyloid A

Suppression subtractive hybridisation (SSH) is a powerful means to identify genes of cytokines and other genes that express small amount of mRNA. In this study, cDNA of normal fish (carp) head kidney cells (HKC) was subtracted from pooled cDNA of HKC and peritoneal cell (PC) obtained from fish which had been injected with sodium alginate (SA) and scleroglucan (SG) 3-48 h earlier. This subtraction produced 248 clones of cDNA fragments. After sequencing some of the fragments of interest were used as probes, and yielded full-length cDNAs homologous to mammalian interleukin-1 beta (IL-1 beta), the gamma subunit of high affinity Fc receptor for IgE (Fc epsilon RI gamma) and serum amyloid A (SAA); these were cloned and sequenced. Carp IL-1 beta shows 21.8-24.7% amino acid identities to mammalian mature IL-1 beta, and lacks a signal sequence, which is consistent with mammalian IL-1 beta. Carp Fc epsilon RI gamma, which was the first cloned non-mammalian Fc receptor subunit, shows 39.3-40.4% amino acid identities to mammalian Fc epsilon RI gamma, and contains the immunoreceptor tyrosin-based activation motif characteristic of the signal transduction subunit of antigen- and Fc-receptors. Carp SAA is most similar to mammalian acute phase responsive type SAA with 53.0-55.3% amino acid identities. Both SA-elicited and SG-elicited PC expressed higher amounts of IL-1 beta and SAA mRNA compared to saline-injected fish HKC and PC, indicating that these proteins are associated with inflammatory responses, similar to mammalian homologues. Fc epsilon RI gamma was constitutively expressed in leucocytes and not immunopotentiator-responsive, but this indicates that Fc receptor including Fc epsilon RI gamma subunit is likely functional in the carp immune system.

Phase I/II study of stage III and IV non-small cell lung cancer patients taking a specific dietary supplement

This phase I/II study evaluates the influence of selected vegetables (SV) that contain known antitumor components on the survival of stage III-IV non-small cell lung cancer (NSCLC) patients. All patients were treated with conventional therapies. SV was added to the daily diet of 5 stage I patients in the toxicity study group (TG) and 6 stage III and IV patients in the treatment group (SVG), but not to the diet of 13 stage III and IV patients in the control group (CG). Age, Karnofsky performance status (KPS), and body mass index of SVG and CG patients were comparable at entry. KPS declined in the CG patients (79 +/- 8 to 55 +/- 11) but improved in the SVG patients (75 +/- 8 to 80 +/- 13) one to three months after entry. Weight change in the CG, SVG, and TG patients was -12 +/- 5%, -2 +/- 2%, and +4 +/- 4%, respectively. The median survival time and mean survival of the CG patients were 4 and 4.8 months, but in the SVG patients they were 15.5 and 15 months (p < 0.01). No clinical signs of toxicity were found in the TG patients in the 24-month study period. Adding SV to the daily diet of NSCLC patients was found to be nontoxic and associated with improved weight maintenance, KPS, and survival of stage III and IV NSCLC patients.

Effects of shiitake (Lentinus edodes) extract on human neutrophils and the U937 monocytic cell line

The aqueous extract of the shiitake mushroom was found to decrease IL-1 production and apoptosis in human neutrophils, as measured by ELISA and flow cytometry respectively. It was found to increase IL-1 production and apoptosis in the U937 monocytic cell line. The extract showed no significant effects on the superoxide production of both neutrophils and U937 cells, as measured by chemiluminescence. The extract was further separated into high and low molecular weight components, and it was found that the low molecular weight component retained the activity of the whole extract. This further suggests that the active substance is a novel compound distinct from lentinan, a well-studied high molecular weight anti-tumour agent found in shiitake.

Effects of intraportal administration of chemoimmunotherapeutic agents on natural killer cell activity in the rat liver

To evaluate the effects of continuous intraportal chemotherapy on tumor immunity of the liver, natural killer (NK) cell activity was estimated in the rat liver. In an in vitro study, NK-enriched mononuclear cells collected from rat liver were incubated with 5-fluorouracil (5-FU) alone and with a 5-fluorouracil/mitomycin C (5-FU/MMC) combination at different concentrations. NK activity was measured after 24-hour incubation. In an in vivo study, the continuous intraportal administration of chemotherapeutic (5-FU/MMC) and chemoimmunotherapeutic (5-FU/MMC/lentinan) agents was carried out in rats for 5 days, and NK-enriched mononuclear cells were then collected from the liver for the measurement of NK activity. Neither 5-FU alone nor the 5-FU/MMC combination affected NK activity in vitro. In the in vivo study, however, the 5-FU/MMC combination significantly decreased NK activity, and the addition of lentinan recovered the activity to the control level. It can thus be concluded that the intraportal administration of chemotherapeutic agents reduces NK activity in the liver and the addition of an immunostimulator to such agents prevents this reduction.

Polysaccharide (ANK-102) from Polianthes tuberosa cells deteriorates the resistance of mice to Listeria monocytogenes infection

Modulatory effect on the murine self defense system by a newly discovered acidic polysaccharide (ANK-102) produced by P. tuberosa cells in liquid culture was examined. Pretreatment with ANK-102 deteriorated the murine survival against lethal infection of Listeria monocytogenes, an intracellular gram-positive bacterium eliminated mainly by macrophages through T-cell mediated immune response. Pretreatment with ANK-102 resulted in the accumulation of Mac 1 and Mac 2 positive cells in the peritoneal cavity of the infected animals and the reduction of Thy1.2 expression on the surface of the thymocytes. A new type of immunosuppressive polysaccharide ANK-102 was introduced.

Application of chemical immunomodulators to the treatment of cancer and AIDS

A number of potential advantages, development of promising new agents, and the discovery of synergy with cytokines or cell products continue to spur research into the application of chemical immunomodulators for the treatment of cancer and AIDS. In preclinical in vitro and in vivo systems, chemical immunomodulators definitely modulate the immune system and have therapeutic efficacy. Although clinical trials have shown the ability of these agents to modulate the human immune system, thus far chemical immunomodulators have generally not fulfilled the therapeutic promise generated in animal models for the treatment of human diseases. While the discrepancy in results between animal models and human trials is obvious, the basis is not apparent. Species differences in elimination kinetics, presentation of active drug at the site of action, and the development of tachyphylaxis have been postulated as reasons for the minimal activity of these agents in humans. In addition, the use of investigational techniques established for cytotoxic agents may not be appropriate for immunomodulators. As with any immunomodulator, determining an optimal immunostimulatory dose and schedule and applying the therapy to patients with minimal tumor burden would perhaps be more appropriate than use of a maximally tolerated dose in patients with advanced disease. A dose-immunological effect relationship has recently been demonstrated for levamisole at doses higher than those used for many years in levamisole trials (99). While research and clinical investigation have identified several potentially useful chemical immunomodulators, the elementary understanding of the biochemical mechanisms involved in immunoregulation remains basic. Future research must elucidate these mechanisms, particularly in humans, to maximize the benefits of chemical immunomodulators as single agents or combined with cytotoxic chemotherapeutic agents, surgery, radiation therapy, other immunomodulators, and antiviral agents.

Enhanced induction of lymphokine-activated killer activity after lentinan administration in patients with gastric carcinoma

In 15 patients with gastric carcinoma, peripheral blood mononuclear cells (PBM) were obtained serially before and 3, 5 and 7 days after lentinan administration. The generation of lymphokine-activated killer (LAK) activity, induced by in vitro activation of PBM with interleukin 2 (IL 2), was significantly augmented 5 days after a single intravenous dose of 2 mg lentinan, when compared with that before lentinan injection. Natural killer (NK) activity of PBM was also significantly enhanced 7 days after the drug injection. However, the distribution of lymphocyte subsets exhibited no significant change following lentinan administration.